Processing method and plasma processing apparatus

ABSTRACT

A substrate processing method includes: providing a substrate in a processing container; selectively forming a first film on a surface of a substrate by plasma enhanced vapor deposition (PECVD); and forming a second film by atomic layer deposition (ALD) in a region of the substrate where the first film does not exist. The second film is formed by repeatedly performing a sequence including: forming a precursor layer on the surface of the substrate; purging an interior of the processing container after forming of the precursor; converting the precursor layer into the second film; and purging a space in the processing container after the converting. A plasma processing apparatus performing the method is also provided.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation in part of U.S. patent applicationSer. No. 16/214,870, filed on Dec. 10, 2018, which claims priority fromJapanese Patent Application No. 2018-109678 filed on Jun. 7, 2018 withthe Japan Patent Office, the disclosures of which are incorporatedherein in their entireties by reference.

TECHNICAL FIELD

An exemplary embodiment of the present disclosure relates to aprocessing method and a plasma processing apparatus.

BACKGROUND

With a decrease in a device size, there is an increasing need for anatomic scale processing such as the atomic layer deposition (ALD). U.S.Patent Laid-Open Publication No. 2017/0140983 discloses a technologythat selectively forms a film on a bottom portion of a pattern by usingplasma modification and atomic layer deposition.

SUMMARY

An embodiment provides a substrate processing method. The processingmethod includes: selectively forming a first film on a surface of asubstrate disposed in a processing container by plasma enhanced chemicalvapor deposition (PECVD); and forming a second film by atomic layerdeposition (ALD) in a region where the first film does not exist.

The foregoing summary is illustrative only and is not intended to be inany way limiting. In addition to the illustrative aspects, embodiments,and features described above, further aspects, embodiments, and featureswill become apparent by reference to the drawings and the followingdetailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flowchart illustrating a processing method according to anembodiment.

FIG. 2 is a view illustrating an example of a configuration of a plasmaprocessing apparatus that performs the method illustrated in theflowchart in FIG. 1.

FIG. 3A is a view illustrating a state of a substrate before performingthe sequence illustrated in FIG. 1, FIG. 3B is a view illustrating astate of the substrate while performing the sequence illustrated in FIG.1, and FIG. 3C is a view illustrating a state of the substrate afterperforming the sequence illustrated in FIG. 1.

FIG. 4A is a view illustrating a state of a film before performing thesequence illustrated in FIG. 1, FIG. 4B is a view illustrating a stateof the film while performing the sequence illustrated in FIG. 1, andFIG. 4C is a view illustrating a state of the film after performing thesequence illustrated in FIG. 1.

FIG. 5 illustrates a change in film thickness of a second film by themethod illustrated in the flowchart in FIG. 1.

FIG. 6 illustrates another aspect of a change in film thickness of thesecond film by the method illustrated in the flowchart in FIG. 1.

FIG. 7A is a view illustrating an example of a state of a first filmformed by isotropic plasma, and FIG. 7B is a view illustrating anexample of a state of a first film formed by anisotropic plasma.

FIG. 8 is a view for explaining an aspect of the film formation andremoval in a case where the first film is formed by anisotropic plasma.

FIG. 9 is a view for explaining an aspect of the film formation andremoval in a case where the first film is formed by anisotropic plasma.

FIG. 10 is a view for explaining an aspect of the film formation andremoval in a case where the first film is formed by anisotropic plasma.

FIG. 11 is a view for explaining an aspect of the film formation andremoval in a case where the first film is formed by anisotropic plasma.

FIG. 12 illustrates an example of an aspect of the first film and thesecond film in a case where the formation of the second film isperformed by unsaturated atomic deposition in the processing methodillustrated in FIG. 1.

FIG. 13 illustrates another example of an aspect of the first film andthe second film in a case where the formation of the second film isperformed by unsaturated atomic deposition in the processing methodillustrated in FIG. 1.

FIG. 14 is a flowchart illustrating an example of a processing method ina case where a second region is etched after forming the second film.

FIG. 15 is a view for explaining an example of the processing methodillustrated in FIG. 14.

FIG. 16 is a view for explaining an example of the processing methodillustrated in FIG. 14.

FIG. 17A is a view for explaining a relationship between an amount offilm formation and a temperature of a substrate, and FIG. 17B is a viewillustrating a state where a substrate is divided into a plurality ofzones.

DESCRIPTION OF EMBODIMENTS

In the following detailed description, reference is made to theaccompanying drawings, which form a part hereof. The illustrativeembodiments described in the detailed description, drawing, and claimsare not meant to be limiting. Other embodiments may be utilized, andother changes may be made without departing from the spirit or scope ofthe subject matter presented here.

The present disclosure provides a technology that improves a selectiveprocessing controllability.

An embodiment provides a substrate processing method. The processingmethod includes: a first process of selectively forming a first film ona surface of a substrate disposed in a processing container by plasmaenhanced chemical vapor deposition (PECVD); and a second process offorming a second film by atomic layer deposition (ALD) in a region wherethe first film does not exist.

Another embodiment provides a substrate processing method. The substrateprocessing method includes: a process of providing a substrate in aprocessing container, a first process of selectively forming a firstfilm on a surface of the substrate by plasma enhanced chemical vapordeposition (PECVD); and a second process of forming a second film byatomic layer deposition (ALD) on a surface of the substrate where thefirst film does not exist. The second process forms a precursor layer ina region of the substrate where the first film does not exist, bysupplying a gaseous precursor into the processing container, purges aninterior of the processing container, and converts the precursor layerinto the second film by exposing the precursor layer to plasma formodification in the processing container, and the plasma formodification reduces a film thickness of the first film.

Still another embodiment provides a plasma processing apparatus. Theplasma processing apparatus includes: a processing container configuredto accommodate a substrate; and a controller configured to control aprocessing performed on the substrate in the processing container, inwhich the controller has a sequence performing unit which repeatedlyperforms a sequence including a first process of selectively forming afirst film on aa selective region of surface of the substrate disposedin the processing container by using plasma enhanced chemical vapordeposition (PECVD), and a second process of forming a second film byatomic layer deposition (ALD) in a region of the surface where the firstfilm does not exist.

As described above, it is possible to improve a selective processingcontrollability.

Hereinafter, various embodiments will be described in detail withreference to the drawings. Further, in the respective drawings, likeparts or corresponding parts will be designated by like referencenumerals.

FIG. 1 is a flowchart illustrating a method of processing a substrate(hereinafter, also referred to as a wafer W) according to an embodiment.Method MT is an embodiment of a processing method. Method MT isperformed by a plasma processing apparatus.

FIG. 2 is a view illustrating an example of the plasma processingapparatus according to the embodiment which is used for method MT. FIG.2 schematically illustrates a cross-sectional structure of a plasmaprocessing apparatus 10 that may be used for various embodiments ofmethod MT. The plasma processing apparatus 10 includes a processingcontainer 12 having a parallel plate type electrode. The processingcontainer 12 accommodates the wafer W. The processing container 12 hasan approximately cylindrical shape, and defines a processing space Sp.The processing container 12 is made of, for example, aluminum, and aninner wall surface of the processing container 12 is anodized. Theprocessing container 12 is grounded for safety.

An approximately cylindrical support unit 14 is provided on a bottomportion of the processing container 12. The support unit 14 is made of,for example, an insulating material. The support unit 14 verticallyextends from the bottom portion of the processing container 12. Inaddition, a placing table PD is provided to be supported by the supportunit 14.

The placing table PD retains the wafer W on an upper surface thereof.The placing table PD has a lower electrode LE and an electrostatic chuckESC. The lower electrode LE includes a first plate 18 a and a secondplate 18 b. The first plate 18 a and the second plate 18 b are made ofmetal such as aluminum and each have an approximately disc shape. Thesecond plate 18 b is provided on the first plate 18 a and electricallyconnected to the first plate 18 a.

The electrostatic chuck ESC is provided on the second plate 18 b. Theelectrostatic chuck ESC has a structure in which an electrode, which isa conductive film, is disposed between a pair of insulating layers or apair of insulating sheets. A DC power source 22 is electricallyconnected to an electrode of the electrostatic chuck ESC through aswitch 23. The electrostatic chuck ESC attracts the wafer W with anelectrostatic force such as a Coulomb's force generated by a DC voltagefrom the DC power source 22.

A focus ring FR is disposed on a peripheral portion of the second plate18 b so as to surround an edge of the wafer W and the electrostaticchuck ESC. The focus ring FR is provided to improve uniformity ofetching. The focus ring FR is made of a material which is selecteddepending on a material of a film to be etched, and the focus ring FRmay be made of, for example, quartz.

A coolant flow path 24 is provided in the second plate 18 b. The coolantflow path 24 is a part of a temperature regulating mechanism. A coolantis supplied into the coolant flow path 24 through a pipe 26 a from achiller unit (not illustrated) provided outside the processing container12. The coolant supplied into the coolant flow path 24 returns to thechiller unit through a pipe 26 b. In this way, the coolant is suppliedinto the coolant flow path 24 so that the coolant circulates in thecoolant flow path 24. A temperature of the wafer W is controlled bycontrolling a temperature of the coolant.

A gas supply line 28 is provided in the plasma processing apparatus 10.The gas supply line 28 supplies heat transfer gas, for example, He gasfrom a heat transfer gas supply mechanism to a portion between an uppersurface of the electrostatic chuck ESC and a rear surface of the waferW.

In addition, a temperature adjusting unit HT such as a heater isprovided in the plasma processing apparatus 10. The temperatureadjusting unit HT is embedded in the second plate 18 b. A heater powersource HP is connected to the temperature adjusting unit HT. As electricpower is supplied to the temperature adjusting unit HT from the heaterpower source HP, such that a temperature of the electrostatic chuck ESCis adjusted, and thus a temperature of the wafer W is adjusted. Further,the temperature adjusting unit HT may be embedded in the electrostaticchuck ESC.

The plasma processing apparatus 10 has an upper electrode 30. The upperelectrode 30 is disposed above the placing table PD and faces theplacing table PD. The lower electrode LE and the upper electrode 30 areprovided approximately in parallel with each other. The processing spaceSp is provided between the upper electrode 30 and the lower electrode LEto perform the plasma processing on the wafer W.

The upper electrode 30 is supported on an upper portion of theprocessing container 12 through an insulating shielding member 32. Theupper electrode 30 may include an electrode plate 34 and an electrodesupport body 36. The electrode plate 34 faces the processing space Spand has multiple gas discharge holes 34 a. In an embodiment, theelectrode plate 34 contains silicon.

The electrode support body 36 detachably supports the electrode plate34. The electrode support body 36 is made of, for example, a conductivematerial such as aluminum. The electrode support body 36 may have acooling structure. A gas diffusion chamber 36 a is provided in theelectrode support body 36. Multiple gas flow holes 36 b, which are incommunication with the gas discharge holes 34 a, extend from the gasdiffusion chamber 36 a to the processing space Sp. In addition, theelectrode support body 36 is provided with a gas introducing port 36 cthat guides a processing gas to the gas diffusion chamber 36 a, and agas supply pipe 38 is connected to the gas introducing port 36 c.

The plasma processing apparatus 10 has a first high-frequency powersource 62 and a second high-frequency power source 64. The firsthigh-frequency power source 62 is a power source that generates firsthigh-frequency electric power for producing plasma and generateshigh-frequency electric power having a frequency of 27 [MHz] to 100[MHz], for example, 60 [MHz]. The first high-frequency power source 62is connected to the upper electrode 30 via a matcher 66. The matcher 66is a circuit that matches output impedance of the first high-frequencypower source 62 and input impedance at a load side (lower electrode LEside). Further, the first high-frequency power source 62 may beconnected to the lower electrode LE via the matcher 66.

The second high-frequency power source 64 is a power source thatgenerates second high-frequency electric power for drawing ions into thewafer W and generates high-frequency bias electric power having afrequency ranging from 400 [kHz] to 40.68 [MHz], for example, afrequency of 13.56 [MHz]. The second high-frequency power source 64 isconnected to the lower electrode LE via a matcher 68. The matcher 68 isa circuit that matches output impedance of the second high-frequencypower source 64 and input impedance at the load side (lower electrode LEside).

The plasma processing apparatus 10 may further have a power source 70.The power source 70 is connected to the upper electrode 30. The powersource 70 applies a voltage, which is used to draw positive ionsexisting in the processing space Sp into the electrode plate 34, to theupper electrode 30. As an example, the power source 70 generates anegative DC voltage. When the voltage is applied to the upper electrode30 from the power source 70, the positive ions existing in theprocessing space Sp are drawn into the electrode plate 34. The drawnions collide with the electrode plate 34, such that secondary electronsand/or silicon are emitted from the electrode plate 34.

A gas discharge plate 48 is provided between the support unit 14 and asidewall of the processing container 12. The gas discharge plate 48 maybe configured, for example, by coating an aluminum member with ceramicssuch as Y₂O₃. A gas discharge port 12 e is provided at a lower side ofthe gas discharge plate 48. A gas discharge device 50 is connected tothe gas discharge port 12 e through a gas discharge pipe 52 and reducespressure in the processing space Sp. A carry-in/out port 12 g for thewafer W is provided in the sidewall of the processing container 12, andthe carry-in/out port 12 g is opened or closed by a gate valve 54.

A gas source group 40 has multiple gas sources. A valve group 42includes multiple valves. A flow rate controller group 45 includesmultiple flow rate controllers such as mass flow controllers.

The plasma processing apparatus 10 may have a post-mixing type structurein which a pipe for supplying a gas having high reactivity such as anaminosilane-based gas and a pipe for supplying another gas areindependently provided to the processing space Sp and the gases aremixed in the processing space Sp. The post-mixing type structure has thegas supply pipe 38 and a gas supply pipe 82. The gas supply pipe 38 andthe gas supply pipe 82 are connected to the gas source group 40 throughthe valve group 42 and the flow rate controller group 45. In thepost-mixing type structure of the plasma processing apparatus 10, a gasline connected to the gas supply pipe 38 and a gas line connected to thegas supply pipe 82 are independently provided between the gas sourcegroup 40 and the valve group 42. In this case, the gas flowing throughthe gas supply pipe 38 and the gas flowing through the gas supply pipe82 are not mixed until the respective gases are supplied into theprocessing container 12.

The gas introducing port 36 c is provided in the electrode support body36. The gas introducing port 36 c is provided above the placing tablePD. The gas introducing port 36 c is connected to a first end of the gassupply pipe 38. A second end of the gas supply pipe 38 is connected tothe valve group 42. The gas is introduced, through the gas introducingport 36 c, into the gas diffusion chamber 36 a formed in the electrodesupport body 36.

A gas introducing port 52 a is provided in the sidewall of theprocessing container 12. The gas introducing port 52 a is connected to afirst end of the gas supply pipe 82. A second end of the gas supply pipe82 is connected to the valve group 42.

A deposit shield 46 is detachably provided in the plasma processingapparatus 10 along the inner wall of the processing container 12. Thedeposit shield 46 is also provided around an outer periphery of thesupport unit 14. The deposit shield 46 inhibits deposits from beingattached to the processing container 12. The deposit shield 46 isconfigured by coating aluminum with ceramics such as Y₂O₃.

The plasma processing apparatus 10 may have a controller Cnt. Thecontroller Cnt controls the processing performed on the wafer W in theprocessing container 12. The controller Cnt is a computer having, forexample, a processor, a storage unit, an input device, and a displaydevice, and controls respective parts of the plasma processing apparatus10. The controller Cnt is connected to, for example, the valve group 42,the flow rate controller group 45, the gas discharge device 50, thefirst high-frequency power source 62, the matcher 66, the secondhigh-frequency power source 64, the matcher 68, the power source 70, andthe heater power source HP. Further, the controller Cnt may control aflow rate and a temperature of a coolant from the chiller unit.

The controller Cnt has a sequence performing unit CS. The sequenceperforming unit CS transmits a control signal by being operated by aprogram based on an inputted recipe. Based on the control signal fromthe controller Cnt, it is possible to control a step of selecting thegas supplied from the gas source group 40, a flow rate of the gas, a gasdischarge by the gas discharge device 50, a power supply from the firsthigh-frequency power source 62 and the second high-frequency powersource 64, and a step of applying a voltage from the power source 70.Further, the controller Cnt may control, for example, the power supplyfrom the heater power source HP, and the coolant flow rate and thecoolant temperature from the chiller unit. Further, respective steps ofa method of processing the wafer W disclosed in the presentspecification may be performed by operating the respective parts of theplasma processing apparatus 10 under control by the sequence performingunit CS of the controller Cnt. The sequence performing unit CS performsthe processing of method MT illustrated in FIG. 1 by operating therespective parts of the plasma processing apparatus 10.

Method MT will be described with reference to FIG. 1. Descriptions willbe made on an example in which the plasma processing apparatus 10 isused to perform method MT. The following description will be made withreference to FIGS. 4A, 4B, 4C, 5, and 6. FIGS. 4A to 4C are viewsillustrating a state of a substrate after performing the respectivesteps of method MT. Method MT includes step ST1 (first step, firstprocessing), step ST5 (second step, second processing), and step ST4.FIGS. 4A, 4B, 4C, and 5 correspond to a case where step ST1 a (cleaningprocessing) is not performed in step ST1, and FIG. 6 corresponds to acase where step STla is performed in step ST1.

Horizontal axes, which are illustrated in FIGS. 5 and 6, respectively,indicate the time from the start of method MT. Vertical axes illustratedin FIGS. 5 and 6 indicate a film thickness of a first film M1 and a filmthickness of a second film M2, respectively. A line LP1 (solid line),which is illustrated in each of FIGS. 5 and 6, indicates a change infilm thickness of the second film M2 formed on a surface SF2. A line LP2(broken line), which is illustrated in each of FIGS. 5 and 6, indicatesa change in film thickness of the first film M1 formed on the surfaceSF2. The first film M1 formed on the surface SF2 includes the first filmM1 formed on the surface SF2 by performing step ST1 for the first time(firstly), and the first film M1 which is formed on a surface of thesecond film M2 on the surface SF2 by performing step ST1 for the secondto subsequent times.

A line LP3 (broken line), which is illustrated in each of FIGS. 5 and 6,indicates a change in film thickness of the first film M1 formed on asurface SF1.

A thickness TH1 a, which is illustrated in each of FIGS. 4A to 4C andFIGS. 5 and 6, is a maximum value of a thickness of the first film M1formed on a surface SF1 by performing step ST1 for the first time. Athickness TH1 b, which is illustrated in each of FIGS. 4A to 4C andFIGS. 5 and 6, is a maximum value of a thickness of the first film M1formed on the surface SF2 by performing step ST1 for the first time.

A thickness TH2, which is illustrated in each of FIGS. 4A to 4C andFIGS. 5 and 6, is a thickness of the first film M1 on the surface SF1 ata timing (timing TMb in the case of FIGS. 4A, 4B, 4C, and 5 and timingTMa2 in the case of FIG. 6) at which the line LP1 starts rising. Athickness TH3, which is illustrated in each of FIGS. 4A to 4C and FIGS.5 and 6, is a thickness of the first film M1 on the surface SF1 at thetiming when step ST5 ends (the timing when step ST1 restarts).

First, the wafer W having a surface SF is prepared. The wafer W isplaced on the placing table PD in the processing container 12 of theplasma processing apparatus 10.

The wafer W has a surface SF. As illustrated in FIGS. 4A to 4C, thesurface SF includes the surface SF1 in a first region (region R1) andthe surface SF2 in a second region (region R2). The region R1 isincluded in a region of the wafer W except for the region R2. The regionR1 and the region R2 may be made of the same material. As an example,both of the region R1 and the region R2 may be made of the same materialincluding silicon.

As another example, the region R1 and the region R2 may be made ofdifferent materials. In this case, the region R1 may be, for example, aphotoresist, a metal-containing mask, or a hard mask. The region R1 maybe made of any one of silicon, an organic substance, and metal. Aspecific example of the material of the region R1 may be any one of Si,SiC, an organic film, metal (W, Ti, WC, etc.), SiON, and SiOC.

Meanwhile, the region R2 may be an etched film which is etched throughthe patterned region RE A specific example of the region R2 may be anyone of SiO₂, SiON, SiOC, and SiN.

In method MT, step ST1 is performed first. A timing TMa1 illustrated inFIGS. 4A to 4C and FIGS. 5 and 6 indicates the timing when step ST1starts when method MT starts, and indicates the timing when step ST5ends while method MT is performed (the timing when step ST1 restarts).

After performing a step of providing a wafer W in the processingcontainer 12, step ST1 selectively forms the first film M1 on thesurface SF of the wafer W disposed in the processing container 12 byplasma enhanced chemical vapor deposition (PECVD). Specifically, filmforming gas and inert gas are supplied into the processing container 12,and high-frequency electric power is supplied, such that plasma isproduced from the supplied gas. The first film M1 is formed on thesurface SF1 in the region R1 of the wafer W by the produced plasma. Inaddition, the first film M1 is formed on the surface SF2 in the regionR2 of the wafer W (FIG. 4A). The first film M1 formed in the region R1is thicker than the first film M1 formed in the region R2.

In step ST1, a carbon-containing gas may be used. For example, whenfluorocarbon gas is used, a fluorocarbon film is formed as the firstfilm M1. In addition, for example, when fluorohydrocarbon gas is used, afluorohydrocarbon film is formed as the first film M1. In addition, forexample, when hydrocarbon gas is used, a hydrocarbon film is formed asthe first film M1. The first film M1 has hydrophobicity. For thisreason, a precursor layer is not formed on the first film M1, and thesecond film M2 is not formed in the subsequent step ST5.

Step ST1 may include the cleaning processing (step ST1 a) for removingthe first film M1 on the surface SF2 (FIG. 6). In this way, step ST1 mayform the first film M1 on the surface of the wafer W, and then mayremove the first film M1 on the surface of the wafer W. In step ST1 a,plasma from oxygen-containing gas, for example, CO₂ gas may be used.

Subsequently, step ST5 is performed. The timing TMa2 illustrated inFIGS. 4A, 4B, 4C, 5, and 6 indicates the timing when step ST5 startsafter step ST1 (the timing when the step ST1 ends).

Step ST5 has a sequence SQ1 and step ST3. Step ST5 forms the second filmM2 by atomic layer deposition in a region of the surface SF of the waferW where the first film M1 does not exist. More specifically, step ST5forms the second film M2 by atomic layer deposition on the exposedsurface SF of the wafer W. The region where the first film M1 does notexist is a region of the surface SF of the wafer W where the first filmM1 is not formed in step ST5. The region in which the first film M1 doesnot exist may further include a region of the surface SF of the wafer Wwhere the first film formed in step ST1 is removed by the plasmaprocessing before step ST5, or also by step ST5. The sequence SQ1includes step ST2 a (third step), step ST2 b (fourth step), step ST2 c(fifth step), and step ST2 d (sixth step). The second film M2 is formedon the surface SF of the wafer W by repeating the sequence SQL Step ST1and step ST5 constitute a sequence SQ2.

The sequence SQ1 represents one cycle of the atomic layer deposition.FIGS. 3A to 3C illustrate a series of steps of the general atomic layerdeposition. The atomic layer deposition forms a precursor layer (layerLy1 illustrated in FIG. 3B) on the surface of the wafer W by usingplasma P1 from second gas G1 (gaseous precursor). Subsequently, thesecond gas G1, which is not adsorbed, is removed by purging theprocessing space Sp. Subsequently, an atomic layer deposition layer(layer Ly2 illustrated in FIG. 3C) is formed by converting the precursorlayer by using plasma for modification. Subsequently, the processingspace Sp is selectively purged.

In the sequence SQ1, step ST2 a supplies the second gas G1 into theprocessing container 12, and forms a precursor layer on a region (e.g.,the surface SF2) of the wafer W where the first film M1 does not exist.The second gas G1 is chemically adsorbed (chemisorption) to the surfaceof the wafer W, such that the precursor layer is formed. Any one ofaminosilane-based gas, silicon-containing gas, titanium-containing gas,hafnium-containing gas, tantalum-containing gas, zirconium-containinggas, and organic substance-containing gas may be used as the second gasG1. In step ST2 a, the plasma from the second gas G1 may be produced ormay not be produced.

Step ST2 b purges the processing space Sp. The second gas G1 in a gasphase state is removed by the purging. For example, step ST2 b purgesthe processing space Sp by supplying inert gas such as argon or nitrogengas into the processing container. In this step, gas molecules attachedin surplus to a surface OPa inside an opening OP are also removed, suchthat the precursor layer becomes a monomolecular layer.

In step ST2 c, the precursor layer is exposed to the plasma formodification in the processing container 12, such that the precursorlayer is converted (modified) into an atomic layer (a part of the secondfilm M2). In this step, third gas is used to convert the precursor layerinto a thin film. The third gas may be any one of oxygen-containing gas,nitrogen-containing gas, and hydrogen-containing gas. The third gas mayinclude any one of, for example, O₂ gas, CO₂ gas, NO gas, SO₂ gas, N₂gas, H₂ gas, and NH₃ gas. Step ST2 c supplies the third gas into theprocessing space Sp. Further, step ST2 c supplies the high-frequencyelectric power from the first high-frequency power source 62 and/or thesecond high-frequency power source 64, thereby producing plasma (plasmafor modification) from the third gas. The produced plasma formodification modifies the precursor layer. In addition, a part of thefirst film M1 is removed by the plasma for modification, such that thefilm thickness of the first film M1 is reduced. Therefore, even thoughthe first film M1 is formed on the surface SF2 by step ST1, the firstfilm M1 is removed from the surface SF2 by performing the sequence SQ1one or more times. In this case, the film thickness of the thin film ofthe first film M1 formed on the surface SF1 is also decreased.

Subsequently, step ST2 d purges the processing space Sp. Specifically,the third gas supplied in step ST2 c is discharged. For example, in stepST2 d, the gas in the processing space Sp may be discharged by supplyinginert gas such as argon or nitrogen gas into the processing space Sp.Further, the sequence SQ1 may not include step ST2 d.

As described above, it is possible to form a layer, which constitutesthe second film M2, on the surface SF2 to the extent of one layer bycompleting one cycle of the sequence SQL The second film M2 is formed onthe surface SF2, which is exposed as the first film M1 is removed, byrepeating the sequence SQL

In the case illustrated in FIGS. 4A, 4B, 4C, and 5, the timing TMbindicates the timing when the first film M1 on the surface SF2 iscompletely removed and the surface SF2 is exposed by performing step ST5(sequence SQ1). In the case illustrated in FIG. 6, the timing TMa2indicates the timing when the first film M1 on the surface SF2 iscompletely removed before performing step ST5 and the surface SF2 isexposed by performing step STla in step ST1.

The first film M1 on the surface SF1 is also removed while performingstep ST5. Therefore, as illustrated in FIGS. 5 and 6, a value of thethickness TH3 of the first film M1 when step ST5 ends is smaller than avalue of the thickness (the thickness TH1 a in the case in FIG. 5 andthe thickness TH2 in the case in FIG. 6) of the first film M1 when stepST5 starts. In addition, in the case in FIG. 5, a value of the thicknessTH2 of the first film M1 on the surface SF1 at the timing TMb is smallerthan a value of the thickness TH1 a of the first film M1 on the surfaceSF1 at the timing TMa2 when step ST5 starts.

Timing TMc illustrated in FIGS. 5 and 6 indicates the timing when thefirst film M1 on the surface SF1 is removed, the surface SF1 is exposed,and the second film M2 starts to be formed on the surface SF1. A lineLP4 (alternate long and short dashes broken line), which is illustratedin each of FIGS. 5 and 6, indicates a change in film thickness of thesecond film M2 on the surface SF1 in the case where the second film M2starts to be formed on the surface SF1 after the timing TMc.

A change in film thickness of the first film M1 and the second film M2in the sequence SQ1 will be described with reference to FIG. 5. Thefirst film M1 is formed on each of the surface SF1 and the surface SF2by step ST1. At the timing TMa2 in the case in FIG. 5 or at the timingTMa3 in the case in FIG. 6, the first film M1 having the thickness TH1 ais formed on the surface SF1 (line LP3), and the first film M1 havingthe thickness TH1 b is formed on the surface SF2 (line LP2).

A forming speed of the first film M1 on the surface SF1 (an inclinationof the line LP3 in step ST1) is higher than (greater than) formingspeeds of the first film M1 and the second film M2 on the surface SF2(an inclination of the line LP2 in step ST1 and an inclination of theline LP1 in step ST5).

In the case in FIG. 5, the first film M1 on the surface SF1 is removedby the continued step ST5, such that the film thickness is decreased. Inthe case in FIG. 6, the first film M1 on the surface SF1 is removed bystep ST1 a (cleaning) which starts at the timing TMa3 while performingstep ST1 and by step ST5 which is continued from step ST1, such that thefilm thickness is decreased. Meanwhile, the first film M1 is removedfrom the surface SF2 by repeating the sequence SQ1, and then the secondfilm M2 is formed on the surface SF2.

The first film M1 on the surface SF1 is removed by repeating thesequence SQ1, and when step ST5 ends, the first film M1 remains on thesurface SF1 or the surface SF1 is exposed. The second film M2 is formedon the surface SF2. Therefore, as illustrated in FIGS. 4A to 4C, at thetiming TMa1 when step ST5 ends, the thickness TH3 of the first film M1on the surface SF1 is zero or smaller than a value of the thickness TH2.

Subsequently, in method MT, step ST3 determines whether to end thesequence SQL Specifically, step ST3 determines whether the number oftimes the sequence SQ1 is repeated reaches a predetermined number oftimes.

The sequence SQ1 is repeated when it is determined that the number oftimes the sequence SQ1 is repeated does not reach the predeterminednumber of times in step ST3 (step ST3: NO). Meanwhile, the sequence SQ1ends in the case when it is determined that the number of times thesequence SQ1 is repeated reaches the predetermined number of times (stepST3: YES). In this way, method MT repeats step ST5 (sequence SQ1)multiple times.

The number of times the sequence SQ1 is repeated may be determined inaccordance with the film thickness of the first film M1. In theembodiment, the number of times the sequence SQ1 is repeated may bedetermined based on the timing when a part of the first film M1 remainson the surface SF1. In another embodiment, the number of times thesequence SQ1 is repeated may be set based on the timing TMc when thefirst film M1 is removed from the surface SF1.

In method MT, the sequence SQ2 is performed one or more times. As thesequence SQ2 is repeated, the first film M1 is formed on the first filmM1 on the surface SF1, as indicated by the line LP3 in FIG. 5. Asindicated by the line LP1 in FIG. 5, the second film M2 is consecutivelyformed on the surface SF2. The sequence SQ2 is repeated until the secondfilm M2 has a target thickness. In the sequence SQ2, the first film M1is formed again by step ST1, and the second film M2 is also formed bystep ST5. Step ST1 and step ST5 may be consecutively performed in thesame processing container (processing container 12) in a state in whicha vacuum is maintained in the processing container.

Subsequently, in method MT, step ST4 determines whether to end thesequence SQ2. More specifically, step ST4 determines whether the numberof times the sequence SQ2 is repeated reaches a predetermined number oftimes.

The sequence SQ2 is repeated when it is determined that the number oftimes the sequence SQ2 is repeated does not reach the predeterminednumber of times in step ST4 (step ST4: NO). Meanwhile, the sequence SQ2ends when it is determined that the number of times the sequence SQ2 isrepeated reaches the predetermined number of times in step ST4 (stepST4: YES).

Here, the number of times the sequence SQ2 is repeated is determinedbased on a target film thickness of the second film M2 on the surfaceSF2. That is, it is possible to adjust the film thickness of the secondfilm M2 by setting the number of times the sequence SQ2 is repeated.

In another embodiment, step ST5 may continue to be performed after thetiming TMa1 for the second time has elapsed. In this case, step ST5 isrepeated even after the first film M1 on the surface SF1 is removed bystep ST5 and the surface SF1 is exposed. As a result, the second film M2is also formed on the surface SF1. Meanwhile, the second film M2 isformed on the surface SF2, such that the second film M2 becomes thicker.

In another embodiment, in step ST1, step STla of cleaning the wafer Wmay be performed after the first film M1 is formed. When step STla isperformed, a part of the first film M1 formed on the surface SF of thewafer W is removed, such that the surface SF2 is exposed. Therefore, thesecond film M2 begins to be formed on the surface SF2 immediately afterstep ST5 starts (FIG. 6 illustrates a change in film thickness of thesecond film M2 formed on the surface SF2 in the region R1). In thiscase, the timing TMa and the timing TMb are the same timing.

As another example, in step ST1, the first film M1, which has differentfilm thicknesses on the surface SF1 and the surface SF2, may be formedby changing a condition of plasma CVD.

For example, in FIG. 7A, the first film M1 is thickly formed on an upperportion of a pattern, and the first film M1 becomes thinner toward abottom portion of the pattern. In FIG. 7B, the first film M1 is formedon the upper portion and the bottom portion of the pattern. The firstfilm M1 formed on the upper portion may be thicker than the first filmformed on the bottom portion. The first film M1 is rarely formed on asidewall of the pattern. Further, the pattern illustrated in FIGS. 7Aand 7B may be formed by etching which is performed before method MT isperformed.

A mode, which uses an anisotropic plasma condition in step ST1, will bedescribed with reference to FIG. 8. A pattern is provided on the surfaceSF of the wafer W. This pattern is formed by etching before method MT isperformed. Here, the region R1 is an upper region (low aspect region).The region R2 is a bottom region (high aspect region). In this example,a surface of the region R1 is referred to as the surface SF1, and asurface of the region R2 is referred to as the surface SF2. As indicatedin a state CD1, the first film M1 is thickly formed on the surface SF1,and the first film M1 is thinly formed on the surface SF2 or the firstfilm M1 is not formed on the surface SF2. The state CD1 indicates anexample in which the first film is not formed on the surface SF2.

The state CD1 indicates a state in which the first film M1 is formed onthe surface SF1 by performing step ST1. The first film M1 is providedonly on the surface SF1. In a case where the first film M1 is formed bystep ST1 on a surface (e.g., the surface SF2) other than the surfaceSF1, the state CD1 is made by removing the first film M1 formed on thesurface other than the surface SF1 by using, for example,oxygen-containing plasma (step ST1 a).

A state CD2 indicates a state of the wafer W at the timing TMa when stepST5, which is performed for the first time, ends and before step ST1 isperformed for the second time. A part of the first film M1 is removed bystep ST5, such that the first film M1 becomes thinner. The second filmM2 is formed on the sidewall and the bottom portion by the atomic layerdeposition in step ST5.

Next, see FIG. 9. A state CD3 indicates a state of the wafer W after thestate CD2, after step ST1 is performed for the second time, and at thetiming TMa when step ST5 starts for the second time. In the state CD3,the first film M1 is formed again as step ST1 is performed for thesecond time.

A state CD4 indicates the wafer W after the state CD3 and at the timingTMa after step ST5 is performed for the second time (before step ST1 isperformed for the third time). The first film M1 is removed by step ST5,such that the first film M1 becomes thinner. On the bottom portion(region R2) of the pattern, the second film M2 is more thickly formed bystep ST5. The sequence SQ2 may be performed multiple times so that thesecond film M2 has a desired thickness. In comparison with the casewhere the first film M1 is thickly formed at a time, the opening (regionR1) is not clogged, and as a result, it is possible to perform thesubsequent step ST5 (atomic layer deposition) with high controllability.

FIG. 10 illustrates still another embodiment. A pattern used in theexemplary is formed by etching which is performed before method MT isperformed. The etching and method MT may be consecutively performed inthe same processing container. A state CD5 indicates a state of thewafer W in a case where the first film M1 is provided in the region R1at an upper side of a structure (feature) and the region R2 of a bottomportion of the structure by performing step ST1 for the first time. Thefirst film M1 is formed on the surface SF1 and the surface SF2.

A state CD6 indicates the wafer W after step ST5 is performed for thefirst time (timing TMa) in the state CD5 and before step ST1 isperformed for the second time. In the state CD6, the first film M1 onthe surface SF1 is removed by step ST5, such that the first film M1becomes thinner. Meanwhile, the first film M1 on the surface SF2 isremoved, such that the surface SF2 is exposed. Meanwhile, the secondfilm M2 is formed on the sidewall (surface SF3) of the structure.

A state CD7 illustrated in FIG. 11 indicates the wafer W when step ST5continues even after the state CD6. When step ST5 is performed, thefirst film M1 on the surface SF1 is removed, such that the surface SF1is exposed. The second film M2 is formed on the surface SF2. The secondfilm M2 on the surface SF3 is thicker than the second film M2 on thesurface SF2.

A state CD8 illustrated in FIG. 11 indicates the wafer W when step ST5continues even after the state CD7. The second film M2 is formed by stepST5 on the surface SF1 which is exposed in the state CD7. The secondfilm M2 becomes thinner in the order of the second film M2 on thesurface SF3, the second film M2 on the surface SF2, and the second filmM2 on the surface SF1. In this way, the second film M2 is formed to havethicknesses that vary depending on the regions including the region R1,the region R2, and the region R3. Here, descriptions have been made onan example in which the anisotropic plasma is used, but the second filmhaving film thicknesses that vary depending on the regions may besimilarly formed by repeating step ST5 even in the case where the firstfilm M1 is formed by isotropic plasma.

Descriptions have been made on the example in which the first film M1 isfurther formed after the state CD6 and the second film having differentfilm thicknesses is formed, but the present disclosure is not limited tothis example, and the region R2 may be etched after the state CD6. Withthis configuration, since the second film M2 is formed on the sidewall(surface SF3) of the structure, it is possible to inhibit bowing duringthe etching. Method MT and the subsequent etching may be performed inthe same processing container. Therefore, throughput may be improved.

(Modification 1: Unsaturated Atomic Deposition)

In step ST5, the second film M2 may be formed sub-conformally, by notsaturating the formation of the precursor layer on the surface of thewafer W in step ST2 a, and/or, not saturating the conversion of theprecursor layer into the second film M2 in step ST2 c. That is, theformation of the second film M2 in step ST5 may be performed by theunsaturated atomic deposition. The unsaturated atomic depositionsatisfies any one of the followings (a) to (c).

-   -   (a) The adsorption of the second gas G1 for forming the        precursor layer in the region where the first film M1 of the        wafer W does not exist is not saturated.    -   (b) The modification of the second gas G1 adsorbed in the region        where the first film M1 of the wafer W does not exist is not        saturated.    -   (c) The modification of the second gas G1 adsorbed in the region        where the adsorption of the second gas G1 and the first film M1        of the wafer W do not exist is not saturated.

The unsaturated atomic deposition may not completely modify the secondgas G1 except for the case where the second gas G1 is not adsorbed tothe entire surface. By the unsaturated atomic deposition, the secondfilm may be sub-conformally formed. More specifically, the second filmM2 may be thickly formed at the upper portion of the pattern, and thesecond film M2 may be thinly formed toward the bottom of the pattern.Except for the above items (a) to (c), for example, the steps andconditions of the unsaturated atomic deposition may be the same as thesteps and conditions of the ordinary atomic deposition described above.Therefore, in step ST5, in a case where the unsaturated atomicdeposition is performed as well instead of a conventional atomicdeposition, a portion of the first film M1 is removed by the third gasin step ST2 c, and the film thickness of the first film M1 is eitherdecreased or disappeared.

In FIGS. 12 and 13, Modification 1 is illustrated in which the formationof the second film M2 in step 5 is performed by the unsaturated atomicdeposition. The pattern used in Modification 1 is formed by the etchingwhich is performed before the method MT is performed. The etching andmethod MT may be consecutively performed in the same processingcontainer (e.g., processing container 12). A state CD9 indicates a stateof the wafer W in a case where the first film M1 is provided in theregion R1 at an upper side of a structure (feature) and the region R2 ofa bottom portion of the structure by performing step ST1 for the firsttime. The first film M1 is formed on the surface SF1 and the surfaceSF2.

A state CD10 indicates the wafer W after step ST5 is performed for thefirst time (timing TMa1) in the state CD9 and before step ST1 isperformed for the second time. In the state CD10, the first film M1 isremoved from the surface SF1 by step ST5, such that the first film M1becomes thinner. Meanwhile, the first film M1 is removed from thesurface SF2, such that the surface SF2 is exposed. Further, the secondfilm M2 is formed on the sidewall (surface SF3) of the structure. InModification 1, since the formation of the second film M2 in step ST5 isperformed by the unsaturated atomic deposition, the second film M2 isthickly formed at the upper portion of the pattern, and becomes thinnertoward the bottom of the pattern. Further, the second film M2 is notformed at the bottom of the pattern regardless of the presence orabsence of the first film M1 in the state CD9.

A state CD11 illustrated in FIG. 13 indicates the wafer W in a casewhere step ST5 continues even after the state CD10. When step ST5 isperformed, the first film M1 on the surface SF1 is removed, such thatthe surface SF1 is exposed.

A state CD12 illustrated in FIG. 13 indicates the wafer W in a casewhere step ST5 continues even after the state CD11. In the state CD12,the second film M2 is formed on the surface SF1 which is exposed by stepST5.

In this way, it is possible to adjust the formation position or the filmthickness of the second film M2 by performing the formation of thesecond film M2 in step ST5 by the unsaturated atomic deposition.

(Modification 2: Change of Processing Condition according to Thicknessof First Film M1)

In a case where step ST5 and the step of etching the wafer W in theprocessing container 12 (step ST6 illustrated in FIG. 14 describedlater) after step ST5 are repeatedly performed, the position and thethickness of the second film M2 may be changed by changing the processconditions of step ST5. That is, descriptions have been made on theexample in which the first film M1 is further formed after the stateCD10 and the second film M2 is formed, but the present disclosure is notlimited to this example, and the region R2 may be etched after the stateCD10. Further, the etching of the region R2, and the sequence SQ1 or thesequence SQ2 may be repeatedly performed. With this configuration, sincethe second film M2 is formed on the sidewall (surface SF3) of thestructure, it is possible to inhibit shape abnormality such as bowingduring the etching.

FIG. 14 is a flowchart illustrating an example of a processing methodwhen the second region R2 is etched after forming the second film M2.FIGS. 15 and 16 are views for explaining an example of the processingmethod illustrated in FIG. 14.

A state CD13 illustrated in FIG. 15 corresponds to the state CD10illustrated in FIG. 12, and indicates a state of the wafer W before theregion R2 is etched. The first film M1 is formed on the surface SF1, andthe second film M2 is sub-conformally formed on the side wall (surfaceSF3). The second film M2 is formed so as to cover a portion immediatelybelow the first film M1 in which the shape abnormality is likely tooccur due to etching.

A state CD14 indicates a state after the etching ST6 is performed forthe first time in the state CD13. The first film M1 is formed on thesurface SF1, and the second film M2 is sub-conformally formed on theside wall (surface SF3). The inner wall of the second film M2 is removedby etching. When step ST5 and step ST6 are repeatedly performed in thestate CD14, the top of the first film M1 is gradually removed such thatthe distance from the top of the first film M1 to the surface SF2 of theregion R2 to be etched is changed (state CD15). In this case, when thesecond film M2 is formed without changing the processing conditions ofstep ST2 a and step ST2 c, the position where the second film M2 isformed is below the position immediately below the first film M1 wherethe shape abnormality occurs.

Therefore, in Modification 2, after the etching (step ST6) and step ST7,it is determined whether the film thickness of the first film M1 is apredetermined value (step ST8). Whether or not the film thickness of thefirst film M1 is a predetermined value may be determined based on thefilm thickness of the first film M1 before step ST is performed and thenumber of times that step ST5 and step ST6 are performed. Then, when itis determined that the film thickness of the first film M1 is apredetermined value (step ST8, YES), the processing conditions of stepST2 a and step ST2 c are reset (step ST9). For example, when theprocessing condition is set such that the coating rate in step ST2 a ischanged along the depth direction of the pattern, the processingcondition is changed such that the second gas G1 is adsorbed only on theupper portion of the pattern. For example, the processing time of thenext step 2 a is set to be shorter than the processing time of theprevious step ST2 a. Further, for example, when the processing conditionis set such that the coating rate in step ST2 c is changed along thedepth direction of the pattern, the processing condition is changed suchthat the third gas reacts only on the upper portion of the pattern. Forexample, the temperature of the processing chamber is lowered.Meanwhile, when it is determined that the film thickness of the firstfilm M1 is not a predetermined value (step ST8, NO), the process returnsto step ST5 without changing the processing conditions.

In this way, it is possible to selectively form the second film M2 on asite where the shape abnormality is likely to occur by adjusting theprocessing conditions according to the film thickness of the first filmM1. For example, in the state CD15, the film thickness of the first filmM1 becomes about half the thickness measured at the start of theprocessing, and the distance from the top to the region R1 to be etchedis shortened. In this case, the distance in the depth direction in whichthe second film M2 is formed is shortened by changing the processingconditions. Then, as in a state CD16, the second film M2 may becontinuously formed at a position where the shape abnormalityimmediately below the first film M1 is likely to occur.

Further, when the shape abnormality occurs in the region R1 to beetched, the pattern shape may be corrected by updating the processingconditions and performing step ST5.

When an aspect ratio of the pattern is increased due to the etching(step ST6), the processing conditions of step ST2 a and step ST2 c maybe changed as the aspect ratio increases. For example, the transportamount of radicals generated in step ST2 c may be increased. That is, asthe number of times the etching (step ST6) is performed is increased,the processing conditions may be changed such that the position wherethe second film M2 is formed is above the region R1 to be etched. Theprocessing conditions may be different processing conditions for eachtime when step ST2 a and step ST2 c are repeated, and may be differentprocessing conditions after repeating step ST2 a and step ST2 c aplurality of times. Further, the processing conditions may be properlychanged depending on factors other than the first film M1.

(Modification 3: Film Thickness Adjustment in Wafer Plane)

In Modification 1 and Modification 2, the coating rate and the filmthickness of the second film M2 are adjusted by adjusting the processingconditions. Meanwhile, the processing conditions in step ST2 a and stepST2 c may be adjusted from the following two viewpoints.

-   -   (1) The film formation position in the depth direction of the        pattern is controlled by controlling a dose amount.    -   (2) The film thickness of the second film M2 to be formed is        controlled.

In Modification 1 and Modification 2, the film formation position iscontrolled mainly from the viewpoint of the above item (1). InModification 3, the processing conditions are adjusted from theviewpoint of the above item (2). That is, in step ST5, the temperatureof the placing table PD on which the wafer W is placed is controlled tohave different temperatures according to the positions, and thethickness of the second film M2 to be formed may be changed according tothe temperature of the placing table PD. FIG. 17A is a view forexplaining a relationship between an amount of film formation and atemperature of the substrate (e.g., wafer W). The horizontal axis inFIG. 17A represents the temperature [° C.] of the wafer W, and thevertical axis in FIG. 17A represents the amount of film formation (nm).The wafer W which is processed in a substrate processing apparatus(e.g., plasma processing apparatus 10) has, for example, a disc shapehaving a diameter of about 300 [mm]. It is known that the amount of filmformation fluctuates depending on the temperature of the wafer W, when afilm formation processing is performed on the wafer W. FIG. 17Aillustrates the relationship between the amount of film formation andthe temperature of the wafer W. As illustrated in FIG. 17A, the amountof film formation increases as the temperature of the wafer W is raised,and the amount of film formation decreases as the temperature of thewafer W is lowered.

Meanwhile, it is known that at the time of processing such as etching,the shape abnormality (e.g., bowing) is relatively small at the centralportion CP of the wafer W, and the shape abnormality tends to increaseat the edge portion EP of the wafer W (see, e.g., FIG. 17B).

Therefore, in Modification 3, as illustrated in FIG. 17B, the placingtable (e.g., electrostatic chuck) of the wafer W is divided into aplurality of concentric zones ZN, and the temperature of each zone ZN isallowed to be independently controlled. Then, the temperature of thecentral portion CP where the shape abnormality tends to be small iscontrolled to be lower than the edge portion EP where the shapeabnormality tends to be large. By controlling in this way, the filmthickness of a protective film to be formed may be adjusted according tothe position in the radial direction of the wafer W, and the in-planeuniformity of the opening dimension to be formed may be improved.

Further, in order to control the film thickness, as illustrated in FIG.17B, the plurality of zones ZN divided in the radial direction as wellas in the circumferential direction are provided such that thetemperature control may be performed independently, such that thetemperature control may be utilized as well as the improvement ofin-plane uniformity. For example, a processing such as forming openingshaving different shapes by changing the thickness of protective film tobe formed for each position of the wafer W may be implemented.

Multiple specific examples of a processing condition, which may be usedfor step ST1, step ST2 a, and step ST2 c, are described in Example 1 andExample 2.

Example 1

The plasma CVD is performed in step ST1. The surface SF of the wafer Wincludes an SiO2 film and a Si mask provided on the SiO₂ film.

<Step ST1>

-   -   Pressure in Processing Space Sp: 20 [mTorr]    -   Electric Power by First High-Frequency Power Source 62: 300 [W]    -   Electric Power by Second High-Frequency Power Source 64: 0 [W]    -   First Gas Flow Rate: C₄F₆ Gas (30 [sccm])/Ar Gas (300 [sccm])    -   Temperature of Wafer W: 40 [° C.]    -   Performance Time: 15 [sec]

<Step ST2 a>

-   -   Pressure in Processing Space Sp: 100 [mTorr]    -   Electric Power by First High-Frequency Power Source 62: 0 [W]    -   Electric Power by Second High-Frequency Power Source 64: 0 [W]    -   First Gas Flow Rate—Aminosilane-based Gas (50 [sccm])    -   Temperature of Wafer W: 10 [° C.]    -   Performance Time: 15 [sec]

<Step ST2 c>

-   -   Pressure in Processing Space Sp: 200 [mTorr]    -   Electric Power by First High-Frequency Power Source 62: 300 [W]    -   Electric Power by Second High-Frequency Power Source 64: 0 [W]    -   First Gas Flow Rate: CO₂ Gas (300 [sccm])    -   Temperature of Wafer W: 10 [° C.]    -   Performance Time: 10 [sec]

Example 2

In Example 2, anisotropic plasma CVD is performed in step ST1. Thesurface SF of the wafer W is divided by the Si mask provided on the SiO₂film of the surface SF of the wafer W.

<Step ST1>

-   -   Pressure in Processing Space Sp: 30 [mTorr]    -   Electric Power by First High-Frequency Power Source 62: 0 [W]    -   Electric Power by Second High-Frequency Power Source 64: 25 [W]    -   First Gas Flow Rate: C₄F₆ Gas (40 [sccm])/Ar Gas (1000 [sccm])    -   Temperature of Wafer W: 60 [° C.]    -   Performance Time: 15 [sec]

<Step ST2 a>

-   -   Pressure in Processing Space Sp: 200 [mTorr]    -   Electric Power by First High-Frequency Power Source 62: 0 [W]    -   Electric Power by Second High-Frequency Power Source 64: 0 [W]    -   First Gas Flow Rate—Aminosilane-based Gas (100 [sccm])    -   Temperature of Wafer W: 60 [° C.]    -   Performance Time: 15 [sec]

<Step ST2 c>

-   -   Pressure in Processing Space Sp: 200 [mTorr]    -   Electric Power by First High-Frequency Power Source 62: 500 [W]    -   Electric Power by Second High-Frequency Power Source 64: 0 [W]    -   First Gas Flow Rate: CO₂ Gas (300 [sccm])    -   Temperature of Wafer W: 60 [° C.]    -   Performance Time: 2 [sec]

In method MT described above, the plasma produced in step ST1 may be anyone of the anisotropic plasma and the isotropic plasma, and the plasmamay be adjusted in accordance with a distribution of the filmthicknesses of the second film M2. In another aspect, step ST1 ofperforming the anisotropic plasma CVD and step ST1 of performing theisotropic plasma CVD may be repeated when repeating the sequence SQ2. Instill another aspect, the anisotropic plasma CVD and the isotropy plasmaCVD may be sequentially performed while step ST1 is performed for thefirst time. In addition, a CVD condition when step ST1 is performed forthe m^(th) (m is a positive integer) time may be different from a CVDcondition when step ST1 is performed for the (m+1)^(th) time. Therefore,the location where the first film M1 is formed may be changed, and as aresult, it is possible to form a distribution of the film thicknesses ofthe first film M1.

In method MT described above, the plasma CVD condition performed in stepST1 may be variously changed. Here, a case where the pattern is providedon the surface of the wafer W by etching is considered. The pattern hasa low aspect region and a high aspect region. In one aspect, the typesof first gas used in step ST1 may be changed. For example, C₄F₆ gas orC₄F₈ gas may be used as the first gas. An attachment coefficient of C₄F₆gas is larger than an attachment coefficient of C₄F₈ gas. Therefore,when C₄F₆ is used, a larger amount of the first film M1 is formed at thesurface side (low aspect region) of the wafer W. Meanwhile, when C₄F₈ isused, a larger amount of the first film M1 is formed at the bottomportion side (high aspect region). In this way, since the attachmentcoefficient varies depending on the types of gas, it is possible tocontrol a position where the first film M1 is formed by changing thetype of gas.

The electric power of the second high-frequency power source 64 may bechanged. As an example, the electric power may be turned on and off. Asanother example, a value of the electric power may be changed between ahigh value and a low value. When the value of the electric power isincreased, the first film M1 is thickly formed on horizontal surfaces(upper surface and bottom portion) of the structure, as illustrated inFIG. 7B. Meanwhile, the first film M1 formed on the sidewall is thin.When the value of the electric power is decreased, a larger amount ofthe first film M1 is formed at an upper side.

In another aspect, a temperature of the wafer at the time of performingstep ST1 may be changed. When the temperature at the time of performingstep ST1 is relatively high, a large amount of the first film M1 isformed at the bottom portion side (high aspect region). When thetemperature at the time of performing step ST1 is relatively low, alarger amount of the first film M1 is formed at the surface side (lowaspect region) of the wafer W.

Pressure at the time of performing step ST1 may be changed. When thepressure is relatively high, the produced plasma is isotropic. Thethicker first film M1 is formed at the surface side (low aspect region)of the wafer W by the isotropic plasma. Meanwhile, when the pressure isrelatively low, the produced plasma is anisotropic. The thicker firstfilm M1 is formed at the bottom portion side (high aspect region) by theanisotropic plasma.

A dissociative state of the plasma may be changed by changing electricpower of the first high-frequency power source 62 at the time ofperforming step ST1. Therefore, produced radical species or a radicalproportion is changed by changing the electric power, and as a result,the attachment coefficient at the time of forming the first film M1 ischanged.

In method MT described above, a condition of a step 5 may be variouslychanged. As an example, it is possible to change the performance time ofstep ST2 c (the time when the plasma is produced). A removal amount ofthe first film M1 may be adjusted by the aforementioned change.

In step ST2 c, it is possible to change electric power of the secondhigh-frequency power source 64. When the electric power of the secondhigh-frequency power source 64 is relatively high, a larger amount ofthe first film M1 on a horizontal portion (the upper surface or thebottom portion) of the structure (feature) is removed. When the electricpower of the second high-frequency power source 64 is relatively low,the amount of removed sidewall portion (sidewall) of the structure ofthe first film M1 is increased.

In step ST2 c, the pressure in the processing container 12 may bechanged. When the pressure is relatively high, energy of ions in theplasma is decreased, such that an isotropic reaction may be dominant.When the pressure is relatively low, energy of ions in the plasma isincreased, such that an anisotropic reaction may be dominant Therefore,it is possible to adjust, by changing the pressure, the region in whichthe first film M1 is removed and the removal amount for each region.

It is possible to change the electric power of the first high-frequencypower source 62 at the time of performing step ST2 c. When the electricpower is relatively high, plasma density may be increased.

With the aforementioned configuration, in the case where step ST1 andstep ST5 are repeatedly performed, one or more conditions among theaforementioned conditions of step ST1 or step ST5 may be differentbetween when the step is performed for the m^(th) (m is a positiveinteger) time and when the step is performed for the (m+1)^(th) time.When the second film M2 is selectively formed in the region R2 byrepeatedly performing the sequence SQ1, one or more conditions among theaforementioned conditions of step ST2 c may be different between whenthe step is performed for the n^(th) (n is a positive integer) time andwhen the step is performed for the (n+1)^(th) time. Therefore,controllability in performing the first film M1 and/or the second filmM2 is improved.

The performance time of step ST2 a is adjusted, for example, within arange of 2 seconds to 10 seconds, and as a result, it is possible tocontrol the removal amount of the first film M1. In this case, theremoval amount of the first film M1 may be 1 [nm] or less (e.g., 0.1[nm] to 0.5 [nm]) for each cycle of the sequence SQL. In addition, inthe case where the second film M2 includes SiO₂, the deposition amountof the second film M2 is a monoatomic layer (i.e., about 0.2 [nm]) foreach cycle of the sequence SQL For example, in a case where fluorocarbonis provided with about 10 [nm] as the first film M1, the first film M1is removed by performing 10 to 100 cycles of the sequence SQ1, and thesecond film M2 is formed with about 2 to 20 [nm]. The first gas forforming the first film M1 is selected in accordance with the purpose,and the first gas may include, for example, a CF-based gas, a CHF-basedgas, a CO gas, or a CH gas.

In method MT, step ST1 and step ST5 may be performed separately in theprocessing container of the plasma processing apparatus. Step ST1 formsthe first film M1 in the region R1 of the wafer W in a first processingcontainer by plasma enhanced chemical vapor deposition by using theplasma from the first gas. Step ST5 forms, by atomic layer deposition,the second film M2 in the region R2 of the surface of the wafer W in asecond processing container where the first film M1 is not formed. Inmethod MT, the step ST1 and step ST5 are repeatedly performed.

Method MT according to the embodiment may be performed by using aninductively coupled plasma processing apparatus. Similar to the plasmaprocessing apparatus 10, the inductively coupled plasma processingapparatus has the gas supply system (the gas source group 40, the valvegroup 42, the flow rate controller group 45, the gas supply pipe 38, thegas supply pipe 82, etc.).

Method MT may be performed solely, but the pattern may be formed byetching the wafer W in the processing container 12 before performingmethod MT. In another aspect, the wafer W may be etched in theprocessing container 12 after performing method MT. Method MT and theetching may be consecutively performed in the same processing containerin a state in which a vacuum is maintained in the processing container.Further, in another aspect, method MT and the etching may be repeatedlyperformed in the same processing container. Since the substrate may beprocessed in the same processing container without transporting thesubstrate, throughput is improved. Meanwhile, method MT and the etchingmay be performed by using separate processing containers. In this case,a plasma exciting method for method MT and a plasma exciting method forthe etching may be different from each other.

From the foregoing, it will be appreciated that various embodiments ofthe present disclosure have been described herein for purposes ofillustration, and that various modifications may be made withoutdeparting from the scope and spirit of the present disclosure.Accordingly, the various embodiments disclosed herein are not intendedto be limiting, with the true scope and spirit being indicated by thefollowing claims.

What is claimed is:
 1. A method of processing a substrate comprising: A)providing a substrate in a plasma chamber, the substrate having asurface on a top thereof and an opening extending downward from thesurface, the opening including a bottom and a sidewall; B) predominantlyforming a first film in a first region on the surface on the top of thesubstrate by plasma enhanced chemical vapor deposition; and C) forming asecond film in a second region of the substrate, wherein the secondregion is on the sidewall of the opening, wherein Step C) comprises asub-step sequence including: C1) supplying the plasma chamber with agaseous precursor to form a precursor layer on the second region of thesubstrate; C2) optionally purging the plasma chamber; C3) exposing theprecursor layer to plasma to convert the precursor layer into a layer ofthe second film; C4) optionally purging the plasma chamber; and whereinduring forming of the second film a thickness of the first filmdecreases, and the second film is formed to have a thickness which isthicker at an upper portion of the opening and thinner more deeply intothe opening.
 2. The method of claim 1, wherein during the predominantlyforming the first film, the first film is formed in the opening, themethod further comprising: removing the first film formed in the openinguntil the first film is removed from the opening.
 3. The method of claim1, wherein the formation of the precursor layer on the second region ofthe substrate is unsaturated in Substep C1) and/or the conversion of theprecursor layer into the layer of the second film is unsaturated inSubstep C3).
 4. The method of claim 1, wherein, in Step C3), the firstfilm deposited on the first region in Step B) is removed and then thesecond film is formed on the first region.
 5. The method of claim 1,wherein the gaseous precursor comprises any one selected from the groupconsisting of an aminosilane gas, a silicon-based gas, a titanium-basedgas, a hafnium-based gas, a tantalum-based gas, a zirconium-based gas,and an organic gas, and wherein the plasma for the conversion of theprecursor layer is generated from any one selected from the groupconsisting of an oxygen-containing gas, a nitrogen-containing gas, and ahydrogen-containing gas.
 6. The method of claim 1, wherein conditions inSubstep C3) differ between the nth (n is a positive integer) cycle andthe (n+1)th cycle.
 7. The method of claim 1, wherein Step B) and Step C)are consecutively performed under reduced pressure in the plasmachamber.
 8. The method of claim 1, wherein, in Step C), the substrate isplaced on a table and the table is controlled to different temperaturesfrom site to site such that the second film has different thicknessesfrom site to site.
 9. The method of claim 1, further including repeatingSteps B) and C) a predetermined number of times.
 10. The method of claim9, wherein: as Step B) and Step C) are repeated, conditions in Step B)differ between the mth (m is a positive integer) cycle and the (m+1)thcycle.
 11. The method of claim 1, further comprising: Bb) etching thesubstrate in the plasma chamber before Step B); and Ca) etching thesubstrate in the plasma chamber after Step C).
 12. The method of claim11, wherein Step C) and Step Ca) are repeated with proviso that thesecond film is formed under different conditions at one or more repeatedcycles such that the position and the thickness of the second film arevaried.
 13. The method of claim 1, wherein during the predominantlyforming the first film, the first film is formed on both the surface onthe top of the substrate and at the bottom of the opening.
 14. Themethod of claim 13, wherein the first film is removed from the bottom ofthe opening during the forming of the second film and the second film isnot formed at the bottom of the opening such that the bottom of theopening is exposed.
 15. The method of claim 13, wherein during formingof the second film, the first film is entrirely removed from the bottomof the opening such that the bottom of the opening is exposed, and afterthe forming of the second film is completed the first film is eitherentirely removed from the surface on the top of the substrate as aresult of the reducing the thickness during the forming of the secondfilm, or a portion of the first film remains on the top of the substratewith a reduced thickness.
 16. A method of processing a substratecomprising: A) providing a substrate in a plasma chamber, the substratehaving a surface on a top thereof and an opening extending downward fromthe surface, the opening including a bottom and a sidewall; B) forming afirst film in a first region of the substrate by plasma enhancedchemical vapor deposition, wherein during the forming of the first film,the first region on which the first film is formed includes at least oneof the surface on the top of the substrate or the bottom of the opening;and C) forming a second film in a second region of the substrate, thesecond region including the sidewall of the opening, Step C) comprising:C1) supplying the plasma chamber with a gaseous precursor to form aprecursor layer on the second region of the substrate, C2) optionallypurging the plasma chamber; and C3) exposing the precursor layer toplasma to convert the precursor layer into a layer of the second filmand to decrease a thickness of the first film, and C4) optionallypurging the plasma chamber, wherein during the forming of the secondfilm, the second film is formed to have a thickness which is thicker atan upper portion of the opening and thinner more deeply into theopening.
 17. The method of claim 16, further including repeating StepsB) and C) a predetermined number of times.
 18. The method of claim 16,wherein during the forming of the first film, the first film is formedon both the surface on the top of the substrate and at the bottom of theopening.
 19. The method of claim 18, wherein during forming of thesecond film, the first film is entrirely removed from the bottom of theopening such that the bottom of the opening is exposed, and after theforming of the second film is completed the first film is eitherentirely removed from the surface on the top of the substrate as aresult of the reducing the thickness during the forming of the secondfilm, or a portion of the first film remains on the top of the substratewith a reduced thickness.
 20. The method of claim 19, wherein duringforming of the second film on the sidewall of the opening, the firstfilm is entirely removed from the surface on the top of the substrate,and thereafter, the second film is formed on the surface on the top ofthe substrate.
 21. A plasma processing apparatus comprising: a plasmachamber for accommodating a substrate; and a controller to control aprocess to be performed on the substrate in the plasma chamber, thesubstrate having a surface on a top thereof and an opening extendingdownward from the surface, the opening including a bottom and asidewall, the controller includes a sequencer that repeats a sequenceincluding: (a) predominantly forming a first film on a first region of asurface of the substrate disposed in the plasma chamber by plasmaenhanced chemical vapor deposition, wherein the first region on whichthe first film is formed includes at least one of the surface on the topof the substrate or the bottom of the opening, and (b) forming a secondfilm in a second region of the substrate, the second region includingthe sidewall of the opening, Step (b) comprising: supplying the plasmachamber with a gaseous precursor to form a precursor layer on the secondregion of the substrate; optionally purging the plasma chamber; exposingthe precursor layer to plasma to convert the precursor layer into alayer of the second film and to decrease a thickness of the first film;and optionally purging the plasma chamber, wherein during the forming ofthe second film, the second film is formed to have a thickness which isthicker at an upper portion of the opening and thinner more deeply intothe opening.
 22. The plasma processing apparatus of claim 21, whereinthe controller controls the apparatus such that during the predominantlyforming of the first film, the first film is formed on both the surfaceon the top of the substrate and at the bottom of the opening.
 23. Theplasma processing apparatus of claim 22, wherein the controller controlsthe apparatus such that during forming of the second film, the firstfilm is entrirely removed from the bottom of the opening such that thebottom of the opening is exposed, and after the forming of the secondfilm is completed the first film is either entirely removed from thesurface on the top of the substrate as a result of the reducing thethickness during the forming of the second film, or a portion of thefirst film remains on the top of the substrate with a reduced thickness.